A crowded commuter train derailed and plowed into an apartment building in western Japan on Monday, turning passenger cars into twisted clumps of metal. At least 49 people were killed and some 340 injured, officials said. The seven-car commuter train was carrying 580 passengers when it jumped the tracks, wrecking an automobile in its path before slamming into a nine-storey apartment complex just yards away. Two of the four derailed cars were flattened against the wall of the building, and hundreds of rescue workers and police swarmed the wreckage and tended to the injured. The cause of the crash in an urban area near Amagasaki, about 250 miles west of Tokyo, was not immediately known, but survivors said excessive speed may have been a factor. Attention focused on the inexperienced, 23-year-old driver, according to a report of the Associated Press.